Fuze test device



Feb. 14, 196 M. E. SHINDLEDECKER 2,971,357

FUZE TEST DEVICE 3 Sheets-Sheet 2 Filed Jan. 30, 1958 INVENTOR. M. E.SHINDLEDECKER ATTYS.

Feb. 14, 1961 Filed Jan. 30, 1958 M. E. SHINDLEDECKER FUZE TEST DEVICE 3Sheets-Sheet 3 M. E. SHINDLEDECKER iy z w ATTYS.

United ates FUZE TEST DEVICE Maurice E. Shindledecker, Laurel, Md.,assignor to the United States of America as represented by the Secretaryof the Navy The invention described herein may be manufactured and usedby or for the Government of the United States of America forgovernmental purposes without the payment of any royalties thereon ortherefor.

This invention relates to a test device for an electric fuze for usewith a projectile and more particularly to a device for simulating thesetback force applied to a fuze as the projectile is fired from a gun,in which means are provided for measuring the interval of time betweenthe application of the simulated setback force to the fuze and theinstant of operation ofthe fuze in time delayed relation with respect tothe application of such force.

Heretofore the methods previously employed for actuating the fuze switchplunger of the electric time delay fuze to set the time delay mechanisminto operation were of the type known as a drop test in which a mass wasdropped from a predetermined height in a manner to impinge uponthe fuzeto effect actuation of the switch plunger thereof or to actually firethe fuze from a gun. Still another method heretofore employed was to usea hammer for obtaining the setback force necessary to set the fuze intooperation. Such methods were inaccurate and costly, the inaccuracy beingdue principally to the lack of proper coordination between theapplication of the setback force and the closure of a timing circuitconcurrently therewith.

The device of the instant invention possesses all of the advantages ofthe prior art devices and methods and none of the foregoingdisadvantages. i

In accordance with the present invention the fuze is set into operationby a rammer or ram comprising a spring actuated plunger releasable froma cockedposition by a solenoid latch arrangement thereby applying thenecessary simulated setback force to the fuze and simultaneouslytherewith completing a control circuit to an electric countingmechanism, the counting mechanism b eing brought to rest when the fuzefires, as will more clearly appear as the description proceeds. t

' One of the objects of the present invention is the provision of a newand improved ram for actuating an electric fuze and completing a controlcircuit simultaneously therewith. r i Another object is a test devicefor an electric fuze havtag new and improved means for suddenlyimparting a simulated setback force thereto and closing a controlcircuit simultaneously with the application of the force.

Still another object is the provision of a time testing [mechanism towhich the fuze to be tested is clamped and which provides a new andimproved ram for setting the fuz e into operation and simultaneouslytherewith starting 3 an electronic counter for measuring the timeinterval before the fuzeperforms a firing operation.

Still other objects, advantages and improvement will be apparent fromthe following description taken into connection with the accompanyingdrawings of which: W 1 Fig.1is a plan View of the test deviceaccordingito a preferred form thereof on which is shown the fuse to betested;

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Fig. 2 is a view in elevation partially broken away and partially insection of the device of Fig. 1; I

Fig. 3 is an end view of the fuze testing device of Fig. 2;

Fig. 4 is a view of the device taken along line 44 of Fig. 1;

Fig. 5 is a view taken along the line 5-5 of Fig. 4;

Fig. 6 is an end view of the fuze clamping mechanism and a fuze clampedthereby; and

Fig. 7 is a schematic diagram of an electrical circuit suitable for usewith the present invention.

Referring now to the drawings on which like numerals of reference areemployed to designate like or similar parts throughout the several viewsand more particularly to Fig. 1 thereof, there is shown thereon in planview, a testing device according to a preferred form of the inventionand indicated generally by the numeral 10. The device comprises a base11 to which is secured as by the bolts 12 a ram mechanism 13 comprisinga block member 14 secured to the base by the bolts 12.

The block member 14 is provided with three axially aligned bores 15, 16and 17 of increasing diameter in the order named, Fig. 4. Within thebores 15, 16 and 17 is disposed for sliding movement a plunger 18 havinga shoulder 19 formed thereon adapted to be brought into engagement withshoulder 21 as the ram is fired. A rod 22 is fitted within bore 23within plunger 18 and secured therein in any suitable manner as by thepin 24 illustrated. A plug 25 is threaded into block member 14 as at 26and provided with a bore 27 within which rod 22 is slide ably disposedin axial alignment with bores 15, 16 and 17. A helical spring 28disposed about rod 22 and having one end thereof in engagement with anend surface of plunger 18 and the other end in engagement with an endsurface of plug 25 is employed to move the rod 22 from the cockedposition of Fig. 4 to the final or rest position shown on Fig. 2 withshoulder 19 thereof engaging shoulder 21 of the block member 14. Theouter end surface of plug 25 is formed at an inclined angle with respectto the axis of rod 22 thereby to form a cam surface 29 for coaction witha complementary cam surface 31 formed on cam member 32, the cam member32 being rotatable in either direction selectively about rod 22.. Theend portion of rod 22 is provided with a-stop member 33 secured theretoin any suitable manner as by the pin 34 illustrated. There is alsoaflixed to cam member 32 a lever or handle 35, Fig. 1, whereby the cammember 32 may be moved from the operated or cocked position of Fig. 4selectively at will to the released position of Fig. 1 after a cockingoperation of the plunger has been achieved. There is also preferablyprovided a guide member 36, Fig. 2, having a cam surface 37 thereon formoving the cam member axially along rod 22 as the lever 35 is restoredafter a cocking operation to the position shown on Fig. 2 such that camsurface 31 thereof engages cam surface 29 of plug 25 throughout theentire surface thereof. The guide member 36 is secured to block member14 in any convenient maner as by the screws 38 illustrated.

The base 11 is provided with an upstanding portion 39 tapped to receivea screw 41 having a round head 42 thereon disposed within a recess 43formed within the block member 14 and retained therein rotatably by theannular member 44 threaded within the block member 14. The screw .41thus provides means for adjusting the block member 14 in a manner tovary the stroke of plunger 18 when .the'screw is rotated by a wrench orother. tool fitted to the machined end 45 thereof. The screwismaintained in anadjusted position by nut 46 threaded thereon when thenut is tightened against the upstanding portion 39 of the base 11.

Secured to the block member 14 as by the screws 47 is a support 48disposed generally transverse to the direction'of movement of plungerIS-and carrying "at the outer portion thereof a solenoid 49 to whichthesupport is secured as by the screws 51, Fig. 5. A magnetic plunger 52 isslideably disposed within the solenoid magnet substantially asillustrated and provided with a bore 53 in the outwardly extendingportion thereof within which is slideably disposed a rod-like latchmember 54 having an elongated slot 55 formed therein and encircling apin 56 secured to plunger 52. An arrangement is thus provided in whichthe plunger 52 applies a sudden axial force to the rod-like member 54when pin 56 has moved to the left, as viewed on Fig. 5, sufficiently toengage the left end of the slot 55. The latch member 54 is disposedwithin a bore 57 formed within block member 14 and the end portion ofthe latch is slideably disposed within bore 58 in alignment with bore 57and communicating with bore 16. The latch member is provided with ahelical spring 59 having one end thereof in engagement with a threadedretaining member 61 and the other end in forcible engagement with washer62 abutting stop pin 63. An arrangement is thus provided in which theoutwardly projecting end of the latch member 54 is urged by spring 59into engagement with cylindrical surface 64 formed on plunger 18 in suchmanner that shoulder 19 of the plunger is latched in a cocked positionby the end portion of latch member 54 until the latch member is suddenlyretracted by operation of solenoid 49.

Secured to base 11 as by bolts 65 is an upstanding bracket 66 having anaperture therein for receiving fuze 67 to be tested. A complementaryclamp member 68 having a pair of downwardly protruding legs 69interconnected by an arcuate surface 71 is employed to clamp the fuze 67tightly against bracket 66, the fuze 67 being provided with an annularraised portion 72 against which the clamping pressure is applied. Thelower end of each of the legs 69 is provided with a downwardlyprojecting cylindrical portion 73, Fig. 2, disposed within a pair ofelongated slots 74 formed within the base 11 in such manner as toprovide a limited degree of movement in 'a direction parallel to theaxis of the fuze and to facilitate the removal of the fuze after test bydisengagement of the clamp member 68 from the base 11. A pair ofadjusting screws 75 are provided within the base 11 for adapting theclamp to different sizes of fuzes 67 to be tested and to provide auniform clamping pressure about the annular raised portion 72 when thefuze is clamped therein. The upper portion of bracket, 66 is providedwith a slot 76'within which is disposed for pivotal movement an eyescrew 77 and secured for pivotal movement in respect thereto as by thepin 78. The upper end of clamp member 68 is also provided with a slottedportion 79 of sufficient width to allow free pivotal movement of the eyescrew 77 therein. The eye screw is threaded as at 81 for threadedengagement with a knurled knob 82 whereby the fuze to be tested isclamped by the clamp member 68 when the eye bolt is in the positionshown on Fig. 2 and the knurled knob 82 is. tightly screwed into aclamping position in engagement with the clamp member 68. The fuze 67 tobe tested is of the type known in the art as .a time delayfuze in whichthe time delay mechanism is set to operation by a force suddenly appliedto. the plunger 83 thereof. When the period of time as originally setinto thefuze has expired, a switch 84 isclosed thereby-completing acircuit across a pair of terminals 85 carried by the fuze. q j

This simulated setback force is applied to plunger 83 ,by a rod'86threadedly securedthereto at one end thereof and at the other endthreadedlysecured to plunger 18.

Plunger 18, it will be -noted,,is provided with a cam surface 87cooperating with cam follower 88 secured to a movable member 89 ofmicroswitch 90.. .Theswitch 99 is disposed within a recess91-formedwithin block "-What is claimed as new and desired to be securedby member 11 and provided with a plurality ofterminals 1 92, 93 and 94and secured to thesblock member 14in anyjsuitable manner as by thescrews 95. I

93'and 9.4..of micro- As shown on Fig. 7 the terminals switch areconnected to the start'circuit or an electronic counter indicatedgenerally by the numeral 96 in such manner that the electronic counteris set into operation when terminals 93 and 94 are closed by the switchin response to movement of plunger 18 from the cocked position as thesolenoid 49 is operated. When the fuze 67 operates at the end of thedelay period the closure of switch 84 thereof causes the electroniccounter to be brought to rest whereby the actual elapsed time betweenthe application of the simulated setback force to fuze 67 and theoperation of the fuze may be made manifest. When the simulated setbackforce has been applied to fuze 67 by plunger 18, the operating circuitto the solenoid 49 is interrupted thereby deenergizing the solenoidplunger 52 causing the plunger to be moved by spring 97 to the positionshown on Fig. 5 and the latch member 54 to be released and brought intoengagement with the plunger 18.

' The operation of the device will best be understood by considerationof a specific example. Let it be assumed, for purpose of descriptionthat a time delay fuze such as the fuze 67 is clamped into the deviceandsecured to the ram by rod 86 and that the plunger 18 has been cockedby reciprocal movement of lever 35 from the position shown on Fig. 2. Asthe lever 35 is moved to a diametrically opposite position from theposition shown on Fig. 2, the cam member 32 secured thereto is rotatedto the position shown on Fig; 4 whereby cocking the ram which is nowlocked in the cocked position by latch member 54- as shown in Fig. 5.The handle or lever 35 is now restored to the initial position of Fig. 2and the cam member 32 connected thereto is moved axially 'along rod 22by-the cam surface 327 of guide member 36 to the position of Fig. 2 suchthat the outer flat surface thereof is disengaged from stop member 33.With the plunger 13 in a cocked position the microswitch is .in theposition shown in solid outline on Fig. 7 with terminal 94 thereof inengagement with terminal 92. As an operating current is applied to thesolenoid 49, the solenoid is energized thereby causing the plunger 52 tobe quickly moved inwardly, and as pin 56 connected to the plungerengages the inner end surface of slot 55 the rodlike latch member 54 issuddenly moved away from shoulder 19 of plunger 18. When this occurs theplunger 18 is moved quickly in a direction of fuze 67 thereby settingthe time release mechanism of the fuze into operation and concurrentlytherewith actuating microswitch 90 to a position interconnectingterminals 94 and 93 thereof thereby setting the electronic counter 96into operation. As switch 84 of fuze 67 is closed at the end eye screw77 upwardly sufficiently for the knob to be disengaged from clamp member68 and the clamp member to be withdrawn from base 11. The fuze 67 maynow be rotated sufficiently to be disengaged from rod 86 or the a rod 86to be disengaged from plunger 18, as the case may be. I

While the invention has been described with particularity with referenceto a preferred example thereof which gives satisfactory results, it isnot so limited, as itwill be apaprent to those skilled in the art towhich the invention pertains, after understanding the invention, thatvarious changes and modifications may be made without departing from thespirit and scope of the invention and it is intended therefore, in theappended claims, to cover all such changes and modifications.

Letters Patent of the United States is:

1. A test device for a projectile fuze comprising means including abifurcated plate for clamping the fu ze to said I device, meansincluding a rod normally in contact with the fuze for applying a suddenforce to the fuze simulating the setback force applied thereto as theprojectile is fired from a gun, said device comprising a frame, asupport mounted within said frame and adjustable therein, a plungersecured to said rod in coaxial relation therewith, said plunger beingslideably mounted in said support and urged in one direction by aspring, cam means including a pair of mutually opposed cam surfaces forretracting said plunger against the urging of said spring from areleased position, a latch pin movably mounted in said support andengageable with said plunger for retaining the plunger in retractedposition, a solenoid mounted on said support and having an armatureconnected to said latch pin by a slot and pin connection, resilientmeans engaging an end of said plunger for yieldably maintaining thelast-named pin in engagement with one end of said slot when the latchpin engages said plunger, said connection permitting the armature tomove and exert a sudden pull on the latch pin to release the plunger asthe pin forcibly strikes the end of said slot, said plunger having a camsurface, a microswitch carried by the support and having a movable partengageable with the cam surface of said plunger, movement of saidplunger from a retracted position to the release position serving to camsaid part to a position closing said microswitch, said microswitchhaving a plurality of electrical terminals for connection to anelectronic counter whereby the electronic counter is set into operationas the micro switch is closed, and means on said fuze and electricallyconnected to the counter for interrupting the operation of the counteras the fuze is fired.

2. A test device according to claim 1 in which the fuze under test is ofthe type which includes means for closing a firing circuit in timedelayed relation with respect to the application of the simulatedsetback force applied thereto, means within the fuze for actuating saidcircuit closing means, andmeans for establishing an electricalconnection between said circuit closing means and the electronic counterthereby to interrupt the operation of the counter as the switch isclosed whereby the time delay of the fuze is made manifest.

3. A fuze testing device comprising means for clamping thereto the fuzeto be tested, a spring driven ram slideably moveable selectively from acocked position to a released position, a rod interconnecting said ramand a fuze to be tested, spring means for quickly moving the ram and rodto said release position, manipulative means having a cam surfacethereon for moving the ram and rod to said cocked position, means forlatching the ram in said cocked position, a solenoid for actuating thelatching means to release said ram thereby to cause the rod to actuatethe fuze, a normally open switch, means including a cam surface on saidram for closing said switch as the ram moves from said cocked positionto the release position, and electronic counting means operativelyconnected to said switch and operable as the switch is closed.

4. A testing device according to claim 3 in which the fuze under testcomprises a normally open switch adapted to be closed in predeterminedtime delay relation with respect to the instant of application of forceto said fuze by the rod, and means including a plurality of electricalcircuit connections for establishing a control circuit from said lastnamed switch to the electronic counting means thereby to interrupt theoperation of the counting means as the last named switch is closed.

5. A projectile fuze tester comprising a base member, means secured tosaid base member for clamping a fuze to be tested, a ram carried by saidbase member and having a bore therein in alignment with the fuze, aspring actuated ram member slideably disposed within said bore andoperatively connected to the fuze for imparting a sudden force theretoas the ram member is actuated from a cocked position to a releasedposition, said force simulating the setback force applied to the fuze asthe projectile is fired from a gun, means operable at will for movingthe ram member to said cocked position, solenoid actuated means forreleasably latching the ram member in said cocked position, and a rigidrod interconnecting the end of said ram member with the fuze wherebysaid sudden force is applied to the fuze by the rod as the ram member isreleased from said cocked position by said solenoid means.

6. A fuze tester according to claim 5 in which the means for clampingthe fuze to be tested comprises a fixed member and a moveable clampingmember, and means operatively connected to said moveable clamping memberfor adjusting the clamped position thereof in a manner to apply aclamping force uniformly to an upraised circumferential portion of saidfuze.

7. A tester according to claim 5 including means settable at will foradjusting the initial and cooked positions of said ram member withrespect to the fuze.

8. A tester according to claim 5 in which the solenoid means includes asolenoid plunger having an axial bore within one end portion thereof, alatch member slideably disposed within said bore and having a slotformed 1ongitudinally therein and a pin secured transversely to saidsolenoid plunger and disposed within said slot for applying a suddenforce to the latch member suflicient to operate the latch member quicklyas the pin strikes one end of said slot in response to the operation ofthe solenoid plunger.

9. A tester according to claim 8 including a spring for yieldably urgingsaid plunger to an unoperated position with the pin normally engagingthe other end of said slot.

10. A tester according to claim 5 including a cam surface on said rammember, a switch disposed in closely spaced adjacency to said camsurface, and a complementary follower on said switch for closing theswitch and engageable by said cam surface as the ram member moves fromsaid cocked position to said reieased position.

References Cited in the file of this patent UNITED STATES PATENTS1,241,213 Heisler Sept. 25, 1917 1,691,170 Schmidt Nov. 13, 19282,037,129 Hilts Apr. 14, 1936 2,689,938 Larson Sept. 21, 1954 2,697,344McNatt Dec. 21, 1954

